Method and apparatus for coiling strip



J. w. OBRIEN, 3,304,023

METHOD AND APPARATUS FOR COILING STRIP Feb. 14, 1967 2 Sheets-Sheet 1 Filed May 18, 1964 INVENTOR JEREMIAH 14 OER/EN ATTOP/VEV.

Feb. 14, 1967 J. w. OBRIEN METHOD AND APPARATUS FOR COILING STRIP 2 Sheets-Sheet 2 Filed May 18, 1964 C ILE INVENTOR. JEQEM/Af/ 14 0819/5 A7' 7' ORA EV.

United States Patent 3,304,023 METHOD AND AllAglATUs FOR COILING T P Jeremiah Wagner OBrien, Mount Lebanon, Pa., assignor to United Engineering and Foundry Company, Pittsburgh, Pa., a corporation of Pennsylvania Fiied May 18, 1964, Ser. No. 368,197 Claims priority, application Great Britain, June 4, 1%3, 22,142/63 7 Claims. (Cl. 24280) This invention relates to a method of and apparatus for coiling strip-like material and, more particularly, to the coiling of metallic strip as it issues from processing equipment, such as, a rolling mill and the like.

While, as indicated above, the present invention may be used in various fields of endeavor, for the purpose of describing a specific embodiment thereof, its application to the coiling of hot metallic strip has been selected. In present-day methods of and apparatuses for coiling such strip as it issues from the last stand of a finishing train of a hot strip mill, it is customary to alternatively feed it to one of two or more tandemly arranged coilers, in which regard, since the mandrels of the coilers are driven at a speed greater than the delivery speed of the mill, all but approximately 500 ft. of the trailing end of the strip is coiled under tension. The influence of tension not only enhances the opportunity of coiling tightly wound coils, but also greatly enhances the ability to guide the strip which significantly contributes to better formed coils which is a fundamental requisite in modern mills.

It was customary, soon after the advent of the continuous hot strip mill, to arrange the two pinch rolls with their axes in a common vertical plane, the pinch rolls being employed to deflect and drive the strip from its horizontal path of travel into the guide throat that led to the coiler. In this arrangement, the guide throat deflected the leading end of the strip in the direction of the coiler.

However, such an arrangement of the pinch rolls did not assure an unhesitant feeding of the strip to the coiler, so that frequent cobbles were experienced, particularly when attempts were made to increase the speed of the mill. In an attempt to alleviate this problem the location of the pinch rolls was changed to the form that they presently take, that is to say, the axis of one of the rolls was arranged angularly in a fixed location relative to the vertical plane and in a direction toward the coiler. This arrangement had the advantage of not only imposing a curvature on the front end of the strip in the direction of the coilers, but the fixed angularly displaced roll had the effect of positively driving the strip toward the coiler and, in addition, it served as a guide for one side of the strip.

Due to the increase in speed and lighter gauges of some types of strip products being produced in a modern strip mill, certain serious shortcomings became evident in the employment of the immediate aforesaid arrangement for coiling strip. One of the shortcomings in oifsetting one of the pinch rolls was that when the strip trailing end left the mill and hence was not being subject to tension created by the mill, but only to the drag created by the pinch rolls, the strip formed an uncontrollable loop at the entry side of the pinch rolls. When such a loop was created in the strip, the effect of the side guards was lost, which were arranged at the entry side of the pinch roll and provided to restrain the strip from moving transversely during coiling. Moreover, this looping of the strip had the tendency to allow certain transverse adjacent portions of the strip to enter the bite of the pinch rolls ahead of other transverse portions, i.e., the strip enters the pinch rolls on a bias, so that the pinch rolls themselves positively urge the strip laterally. The difiiculty in restraining the strip against lateral movement was aggravated by misalign- 3,364,621; Patented Feb. 14, 1967 ICC ments of the pinch rolls and by the wear of the parts thereof, which added to the tendency of the strip to move laterally. The net result was that the trailing end portion of the strip was unevenly wound about the mandrel. Since this portion may, in a given case, represent a third of the length of the coil, the seriousness of the problem becomes self-evident.

The present invention is addressed to a method of and apparatus for alleviating each of the aforesaid disadvantages.

It is one of the objects of the present invention to provide a method for coiling evenly formed coils of strip, which when related to a strip mill contemplates the use of a coiler and a pair of pinch rolls that engage the strip for at least a part of the time it is being coiled, the steps of arranging one of said pinch rolls in a first position prior to the strip issuing to the coiler, so that one roll is displaced away from a vertical plane containing the axis of the other roll thereof and in the direction of the coiler, coiling the leading portion of the strip when said one roll is in its first position, coiling the succeeding portion of the strip under tension created by the mill and coiler after a portion of the leading portion thereof is tightly wrapped around the mandrel, positioning said one roll in a second position so that its axis falls substantially within the vertical plane containing the axis of the other pinch roll prior to the trailing portion of the strip leaving the mill, and coiling the trailing portion of the strip under tension created by said pinch rolls and mandrel, while the said one roll is in the second position.

The method herein disclosed also contemplates when a econd or third coiler is being employed, the additional step of employing the pinch rolls of a previous coiler to maintain a tension on the strip between the previous pinch rolls and the succeeding coiler. In an arrangement wherein the first pinch rolls are thusly employed, the pinch rolls of the coilers other than the first need not be made shiftable relative to each other.

With respect to the apparatus herein disclosed for carrying out, in part, the aforesaid method, there is provided a novel pinch roll arrangement wherein means are provided for shifting one of the rolls relative to the other and wherein the shiftable pinch roll may be positioned with its axis located in a plane substantially perpendicw lar to the path of the strip or in a plane oblique relative to this path.

These and other features and advantages of the present invention will be more fully appreciated and understood when the following description is read in the light of the accompanying drawings in which:

FIGURE 1 is a diagrammatical elevational view of the finishing arrangement of a hot strip mill showing the last stand of the finishing train thereof, in addition to three tandemly arranged pinch roll assemblies and coilers,

FIGURE 2 is an elevation view, partly in section, of the first pinch roll assemby shown in FIGURE 1,

FIGURE 3 is a partial sectional view, which section as taken on line IIIIII of FIGURE 2, of the pinch roll assembly shown in FIGURE 2, and

FIGURE 4 is a partial sectional view, the partial section being taken on line IVIV of FIGURE 2.

With reference to FIGURE 1, there is schematically illustrated the last stand 10 of a hot strip mill. Spaced from the mill at a distance of approximately 450 ft. there is located a battery of strip coilers which in the illustration consists of three in number, namely, 11, 12 and 13, reading from right to left. A strip S, moving in the direction indicated by the arrow, is conveyed from the stand 10 to the coilers by tables 14, 15 and 16. Each coiler has its own cooperating pinch roll assembly 17, 18 .and 19, respectively, the pinch roll assembly 17 incorporating the structural features of the present invention. It is believed unnecessary to discuss in detail the characteristics of the stand 10, the coilers 11-13, or the tables 14- 16 as they are well-known in the rolling mill art.

With reference now to the construction of the pinch roll assembly 17, reference will be made to FIGURES 2, 3 and 4. As FIGURE 2 illustrates, the pinch roll assembly consists of a lower pinch roll 21 which is rotatably received in a frame 22, the opposite ends of the roll being provided with well-known bearing-chock assemblies, not shown. FIGURE 2 shows that the roll 21 is located close to the upper opening of the throat 23 that extends between the bite of the pinch rolls and the mandrel of the coiler and that its upper peripheral surface falls substantially within the path of travel of the strip S. The upper pinch roll 24 of the pinch roll assembly 17 is rotatably mounted in a pivotal frame 25, the opposite ends of this roll being received in well-known bearing-chock assemblies, not shown. The frame 25 is raised and lowered through the agency of a piston cylinder assembly 25a. It is to be appreciated that while not shown, both of the pinch rolls are provided with a drive that rotates the rolls at the speed slightly in excess of the strip speed as it issues from the rolling mill. Since the upper pinch roll 24, as will be explained later, is moved arcuately relative to the lower pinch roll 21, the drive thereof may include a universal spindle.

With reference again to the frame 25, as shown best in FIGURE 3, it is carried on a transversely arranged shaft 26 about which the frame rotates by virtue of bushings 27. At the opposite ends of the shaft, there are provided identical cranks 28, which are received in a pair of spaced apart frame members 29, the amount of arcuate movement of the pinch roll 24 being a function of the eccentricity of the cranks 28. FIGURE 3 shows one of these cranks which at the outer end thereof a gear 30 is secured. The gear 30 meshes with a sector gear 31, the other end of the sector gear being keyed to a transversely arranged shaft 32. This shaft is rotatably received in the frame members 29 and at its extreme opposite end an arm 32a is provided, to which is connected a piston cylinder assembly 33, the cylinder being carried by a support 33a which extends between the frame members 29. On the operation of the piston cylinder assembly 33 the shaft 32 rotates the sector gear 31 and, in turn, the gear 30 which will rotate the cranks 28 and, accordingly, displace the shaft 26 so that the pinch roll 24 will move in an arcuate direction longitudinally of the strip around the upper periphery of the lower pinch roll 21 so to speak. In this manner the pinch roll 24 may be moved to an off-center position as indicated in a full line in FIGURE 2 or to a second position where its axis falls within the vertical plane containing the axis of the lower pinch roll 21, which position is shown in outline form in FIGURE 2. By reason of the abovedescribed construction of the pinch rolls and, as previously noted, the pinch rolls are employed alternately to defleet the strip into an oblique path of travel or to serve as a strip tensioning means.

In certain arrangements, immediately preceding the pinch rol-l assembly 17, there may be provided three strip guide rollers which are the subject matter of US. application No. 359,351 in which connection it may be desirable to design the pivotal upper pinch roll 24 to cooperate with the strip holddown roller of the guiding arrangemnt. Of course a more simplified strip guiding arrangement could be substituted for the one shown.

In this connection, as illustrated in FIGURE 2, there is provided strip guiding rollers 34, 35 and 36. The former two rolls have concentric collars that serve to restrain lateral movement of the strip. The upper strip holddown roller 36 is connected to an arm 37 which is carried by the shaft 32. With reference to FIGURE 3, it will be noted that the arm 37, the lower end of which is shown in section in this figure, takes the form of a concentric sleeve 38 which is supported by and rotates relative to the shaft 32. To the one end of this sleeve, there is connected an arm 39, to the outer end of which the piston rod of a piston cylinder assembly 41 is connected. This cylinder is also carried by the cross member 33a, which, as previously noted, is supported by the two frame members 29.

In one form of the invention the pressure in the piston cylinder assembly 41 is maintained at a low magnitude so that upon operation of the piston cylinder assembly 33, the upper pinch roll 24 is adapted to engage the arm 37 of the roller 36 and displace it to a position intermediate the full line and dash line positions thereof shown in FIGURE 2. In this way the roller 36 will not interfere with the independent movement of the upper pinch roll 24. To facilitate this, the pivotal frame 25 that carries the upper pinch roll 24 is provided with a cam roller 42 arranged at the lower end of the strip holddown roller 36, the cam roller being shown best in FIGURE 4 As FIGURE 4 shows, the cam roller 42 is adapted to be engaged by a bearing 42a extending from the one end of the roller 36.

With reference to the method herein disclosed for coiling strip issuing from the hot strip mill and in referring to FIGURE 1, let it be assumed that a strip S is to be coiled in the coiler 11, in which connection prior to the strip being received by' the coiler, the coiler will be brought up to a speed slightly in excess of the speed of the stand 10 and the upper roll 24 of the pinch roll assembly 17 will be shifted to its offset position, as illus trated in full line in FIGURE 2. The leading end of the strip issuing from the stand 10 will be conveyed over the table 14 to the pinch roll assembly 17 which because of the offset position of the upper roll 24 will urge it into the coiler 11. As previously mentioned, the pinch roll is driven at a speed slightly greater than the speed of the strip which is determined by the speed of the stand 10;

After several convolutions have been wrapped around the mandrel of the coiler 11, in view of the fact that the coiler is rotating at a greater speed than the strip speed, tension will be eventually imposed upon the strip, at which point the mill will force the coilers to assume the speed of the mill. At this instance, the upper pinch roll 24 is raised out of the pinching relationship with the strip which position as shown in outline form in FIGURE 2 and immediately thereafter the pinch roll 24 is moved 7 to the on-center position shown in FIGURE 1, in anticipation of the trailing end leaving the stand 10. When the trailing end of the strip is passing through the finishing mill and prior to its passing through the stand 10, a signal is given by one of the earlier stands, not shown, such as from a load cell, to effect operation of the piston cylinder assemblies 25a, whereby the upper pinch roll will be again brought into a pinching engagement with the strip prior to the trailing end leaving the stand 10. Once the trailing end of the strip has left the stand 10, as previously noted, the strip will not be subject to the tension created between the stand 10 and the coiler 11. The pinch roll assembly 17, however, will maintain tension between the coiler and itself. In addition, as previously mentioned, in view of the fact that the upper pinch roll 24 is moved to its oncenter position, the strip will not have the tendency to loop or buckle at the entry side of the pinch roll assembly and the side guards will be better able to confine the strip from moving transversely. As a result, the last convolutions of the coil will be tightly formed and a properly formed coil will be assured.

With reference to the operation of coiling a strip in one of the other two coilers, namely 12 or 13, let it be assumed that the strip S is to be received by the coiler 12. In this instance the upper pinch roll of the pinch roll assembly 18 need not be provided with the ability to shift to the on-center position but the usual means will be provided for raising and lowering the upper pinch roll relative to the strip. Accordingly, prior to the strip being received by the coiler 12, the coiler will be brought to its operating speed and the upper pinch roll of the pinch roll assembly 18 lowered to engage the strip; the upper pinch roll 24 of the pinch roll assembly 17 will be shifted to its on-center position but held out of engagement with the strip by the operation of the piston cylinder assembly 25a in readiness to engage the trailing end thereof. The leading end of the strip will thus be coiled as in the case described relative to the coiler 11. Once the mandrel of the coiler 12 has established a tension between itself and the stand 10, the upper roll of the pinch roll assembly 18 will be raised away from the strip.

Prior to the trailing end of the strip leaving the stand 10, the upper pinch rolls of the pinch roll assemblies 17 and 18 will be lowered as previously explained with respect to the pinch roll 24, to subject the strip to tension between the two pinch roll assemblies and the coiler 12. In coiling strip in this method there will result the advantage that the strip will be maintained under a substantial tension for almost the entire coiling procedure. In this regard it will be noted that while the upper roll of the pinch roll assembly 18 is arranged in an off-center position, the tension developed by the pinch roll assembly 17 will prevent the strip from buckling at the entry side of the pinch roll assembly 18, thereby assuring proper guiding of the last convolutions of the strip.

It will be appreciated that the method and apparatus herein disclosed may be modified .to suit a particular condition. Accordingly, while the upper roll 24 of the pinch roll assembly 17 is disclosed as moving relative to the lower roll, the converse may just as well be employed. Also, the second pinch roll assembly may be constructed to operate in the same fashion as the first assembly, when strip is being coiled in the third coiler, if one is employed.

In accordance with the provisions of the patent statutes, I have explained the principle and operation of my invention and have illustrated and described what I consider to represent the best embodiment thereof. However, I desire to have it understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

Iclaim:

1. In a method of coiling strip-like material in a strip winding machine after the strip issues from a processing apparatus, including va strip tensioning device comprising the steps of:

conveying in a first direction of travel the leading end of the strip from said processing apparatus to said tension device,

positioning said tension device to deflect the leading end of the strip into a second direction of travel and to urge it toward said winding machine, creating a tension on the strip between the winding machine and the processing apparatus after the leading end of the strip is in said winding machine, and

positioning said tension device to impose a tension on the trailing end of the strip While tending to urge the trailing end in said first directon of travel.

2. In a method of coiling strip-like material, according to claim 1, in which said tension device is alternately positionable in a strip-deflecting position and a strip-tensioning position comprising the steps of positioning said tension device in its strip-deflecting position to feed the leading end of the strip to said winding machine, and thereafter,

positioning the tension device in its strip-tensioning position prior to the trailing end of the strip leaving said processing apparatus, thereby to continue to subject the strip to tension during its coiling after the tension imposed on the strip between the winding machine and processing apparatus terminates by reason of trailing end leaving the latter.

3. In a method of coiling strip-like material according to claim 1, including the steps of:

maintaining the tension device in a non-tensioning condition during the passage of the strip, except for the trailing end thereof.

4. In a method of coiling strip-like material, according to claim 1, in which there is provided in spaced sequence at least two winding machines, one being positioned farther away from said processing apparatus than the other,

said winding machines receiving and coiling successively issued strips, and

a strip tension device associated with each winding machine comprising the steps of:

positioning said strip tension device associated with the fartherest positioned winding machine to feed the leading end of the strip to said fartherest positioned winding machine, and

thereafter positioning the tensioning devices of both winding machines to impose a tension upon the trailing end of the strip.

5. In a pinch roll apparatus for use with a coiler adapted to coi-l strip-like material comprising:

a lower roll over which the strip passes and by which it is supported,

an upper roll under which the strip passes,

means for moving one of said rolls in a direction rela tive to the path of travel of the strip and to the other roll to place said rolls alternately in a strip-feeding or a strip-tensioning position, and

means for moving one of said rolls towards the path of travel of said strip to cause said rolls to pinch the strip when in said strip tensioning position.

6. In a pinch roll apparatus, according to claim 5, wherein said upper pinch roll is carried by a pivotal frame,

said means for moving said upper rolls towards said path of travel of the strip being connected to said frame to move said upper roll toward and away from said lower roll,

a shaft for pivotally supporting said frame,

an eccentric for rotating said shaft, and

means for rotating said eccentric to move said upper roll longitudinally relative to the path of travel of the strip.

7. In a pinch roll apparatus, according to claim 6, including a strip guiding mechanism,

which includes means for engaging the upper surface of the strip to assist in guiding it into said pinch rolls, means for moving the strip-engaging means toward and away from said strip, said strip-engaging means in its position away from said strip being engageable by said upper pinch roll,

said means for moving the strip-engaging means and said means for moving the upper pinch roll being so constructed and operated that on movement of the upper pinch roll in a direction toward said stripengaging means, the latter will be displaced to allow movement of the upper pinch roll.

References Cited by the Examiner UNITED STATES PATENTS 6/1943 Sablin 266 X 8/1963 Bond 2428O 

1. IN A METHOD OF COILING STRIP-LIKE MATERIAL IN A STRIP WINDING MACHINE AFTER THE STRIP ISSUES FROM A PROCESSING APPARATUS, INCLUDING A STRIP TENSIONING DEVICE COMPRISING THE STEPS OF: CONVEYING IN A FIRST DIRECTION OF TRAVEL THE LEADING END OF THE STRIP FROM SAID PROCESSING APPARATUS TO SAID TENSION DEVICE, POSITIONING SAID TENSION DEVICE TO DEFLECT THE LEADING END OF THE STRIP INTO A SECOND DIRECTION OF TRAVEL AND TO URGE IT TOWARD SAID WINDING MACHINE, CREATING A TENSION ON THE STRIP BETWEEN THE WINDING MACHINE AND THE PROCESSING APPARATUS AFTER THE LEADING END OF THE STRIP IS IN SAID WINDING MACHINE, AND POSITIONING SAID TENSION DEVICE TO IMPOSE A TENSION ON THE TRAILING END OF THE STRIP WHILE TENDING TO URGE THE TRAILING END IN SAID FIRST DIRECTION OF TRAVEL. 